Zero-Downtime Deployment enables updates to be rolled out to users without impacting their experience. Instead of taking the application offline during updates, Zero-Downtime Deployment ensures that users can continue to access the application throughout the deployment process. This is typically achieved by deploying the new version alongside the existing version and then gradually shifting user traffic from the old version to the new one.
For example, let's say you are updating an e-commerce website to add new features. With Zero-Downtime Deployment, you can deploy the new features without interrupting ongoing transactions. This means that customers can continue to browse, add items to their cart, and make purchases without any disruption, even while the updates are being deployed.